Harris was born in Oakland, California, ^[10] on October 20, 1964. ^[11] Her mother, Shyamala Gopalan, a biologist whose work on the progesterone receptor gene stimulated advances in breast cancer research, ^[12] had arrived in the US from Tamil Nadu in India in 1958 as a 19-year-old graduate student in nutrition and endocrinology at the University of California, Berkeley ; ^[13] [14] Gopalan received her Ph.D. in 1964. ^[15] Her father, Donald J. Harris, is a Stanford University professor emeritus of economics, who arrived in the US from British Jamaica in 1961 for graduate study at UC Berkeley, receiving a Ph.D. in economics in 1966. ^[16] [17] Along with her younger sister, Maya, Harris lived in Berkeley, California, ^[18] [19] briefly on Milvia Street in central Berkeley, then a duplex on Bancroft Way in West Berkeley, an area often called "the flatlands" ^[20] with a significant black population. ^[21]

When Harris began kindergarten, she was bused as part of Berkeley's comprehensive desegregation program to Thousand Oaks Elementary School, a public school in a more prosperous neighborhood in northern Berkeley ^[20] which previously had been 95 percent white, and after the desegregation plan went into effect became 40 percent, Black. ^[21] A neighbor regularly took the Harris girls to an African American church in Oakland where they sang in the children's choir. ^[22] [23] Their mother introduced them to Hinduism and took them to a nearby Hindu temple, where she occasionally sang. ^[24] As children, she and her sister visited their mother's family in Madras (now Chennai ) several times. ^[25] She says she has been strongly influenced by her maternal grandfather PV Gopalan, a retired Indian civil servant whose progressive views on democracy and women's rights impressed her. Harris has remained in touch with her Indian aunts and uncles throughout her adult life. ^[26] Harris has also visited her father's family in Jamaica. ^[27]

Her parents divorced when she was seven. Harris has said that when she and her sister visited their father in Palo Alto on weekends, other children in the neighborhood were not allowed to play with them because they were black. ^[25] When she was twelve, Harris and her sister moved with their mother to Montreal, Quebec, Canada, where Shyamala had accepted a research and teaching position at the McGill University -affiliated Jewish General Hospital. ^[28] She attended a French-speaking primary school, Notre-Dame-des-Neiges, ^[29] and then Westmount High School ^[b] in Westmount, Quebec, graduating in 1981. ^[31] Wanda Kagan, a high school friend of Harris, later told CBC News in 2020 that Harris was her best friend and described how she confided in Harris that she had been molested by her stepfather. ^[32] She said that Harris told her mother, who then insisted Kagan come to live with them for the remainder of her final year of high school. Kagan said Harris had recently told her that their friendship, and playing a role in countering Kagan's exploitation, helped form the commitment Harris felt in protecting women and children as a prosecutor. After high school, in 1982, Harris attended Howard University, a historically black university in Washington, DC While at Howard, she interned as a mailroom clerk for California senator Alan Cranston, chaired the economics society, led the debate team, and joined Alpha Kappa Alpha sorority. ^[33] [34] Harris graduated from Howard in 1986 with a degree in political science and economics.